Nicolas Gangnet

New interspinous implant evaluation using an in vitro biomechanical study combined with a finite-element analysis.

Study Design. A combined in vitro and finite-element analysis was completed to assess the biomechanical effect of a new interspinous implant on the lumbar spine. Objective. The aim was to investigate the effect of an interspinous implant on the biomechanical behavior of a vertebral segment. Methods. An in vitro study on L3–L5 segments from fresh human cadavers was conducted combined with a 3-dimensional finite-element analysis. Intact, injured, and instrumented states of L4–L5 were compared loaded in flexion-extension, lateral-bending, and torsion. The evaluated implant is an interspinous spacer fixed to the spine by 2 polyester braids looped around the proximal and distal spinous. Results. The effect of the implant appeared mainly in flexion-extension: experimental results showed reduced range of motion of the instrumented spine regarding the injured and intact one; and finite-element analysis indicated a decrease of disc stresses and increase of loads transmitted to the spinous processes. Conclusion. In this in vitro and finite-element analysis, the role of the new interspinous implant appeared to reduce motion without suppressing it and to lower stress in the disc fibers and anulus matrix. Further in vivo investigations are necessary to draw definitive conclusions.

Anterior Approach to the Cervicothoracic Junction Without Sternotomy : A Report of 37 Cases

Study Design. Description of a new anterior approach to the cervicothoracic junction and retrospective study of results. Objective. To propose a less invasive anterior approach and report the preliminary results of this technique. Summary of Background Data. Different partial sternotomies with or without associated clavicular resection have been proposed but expose patients to the risk of pseudarthrosis. A less invasive technique should reduce the morbidity of this surgery. Methods. From 2000 to 2004, 37 patients were operated between T1 and T4. Whenever possible, access was limited to a left standard cervical approach anterior to the carotid sheath extended caudally. If necessary, partial manubrial resection preserving the sternoclavicular joints was performed to extend the exposure. In the majority of cases, metastatic spinal cord compression was involved. Results. The average duration of surgery was 114 minutes; the average blood loss was 760 mL. For access to the vertebral body of T2, a standard anterior cervical approach alone was always sufficient. For exposure of T3 and T4, median manubrial resection was performed in roughly 1 case out of 2. This was used in every case for T5. There were 4 severe and 3 mild complications. Conclusion. This approach provides satisfactory access to the anterior aspect of the spine down to T5 while preserving the sternoclavicular joints.

Total Vertebrectomy and Spine Shortening in the Management of Acute Thoracic Spine Fracture Dislocation: Technical Note and Report of 3 Cases

Study Design Case report of 3 thoracic spine fracture-dislocations with complete spinal cord section treated by total vertebrectomy—spine shortening through a posterior approach. Objectives To assess the usefulness and safety of this surgical technique in the treatment of acute thoracic spine fracture-dislocation. Summary of Background Total vertebrectomy can be used in different nontraumatic disorders. This surgical procedure has been used in the chronic phase of traumatic thoracolumbar dislocation. To our knowledge, the technique of total vertebrectomy and spine shortening in the acute phase of thoracic spine fracture dislocation has never been reported. Material and Methods Three patients who suffered thoracic spine fracture-dislocation with ASIA A paraplegia underwent complete vertebrectomy and spine shortening through a posterior approach. We report technical details, clinical, and radiologic results at 24 months minimum follow-up. Results Complete vertebrectomy of the fractured vertebra involved T5 in 1 patient, T7 in another, and T10 in the third. There were no perioperative complications. At latest follow-up, fusion was obtained in all 3. Overall sagittal and coronal alignment was restored. Conclusions Complete vertebrectomy and spinal shortening can be used in the acute phase to manage thoracic spine fracture-dislocations.

Hernie discale thoracique T1-T2: À propos de 2 cas

Resume Nous rapportons deux cas de localisation rare de hernie discale thoracique T1-T2 chez un homme de 60 ans et chez une femme de 55 ans. Le premier cas etait traite chirurgicalement. Le second etait traite medicalement. Les lesions arthrosiques ont semble etre la cause determinante. Une hernie molle et postero-laterale etait observee, contrairement aux hernies habituellement calcifiees et postero medianes de l’etage moyen ou inferieur du rachis thoracique. La symptomatologie se resumait dans les deux cas par une radiculopathie T1 a distinguer d’une radiculopathie C8. La myelopathie est rare. Le syndrome de Claude Bernard Horner est inconstant mais evocateur. Ces deux signes etaient absents chez nos patients. La hernie discale thoracique T1-T2 doit etre suspectee devant toute nevralgie cervico-brachiale mediane. Le diagnostic repose sur l’IRM. La chirurgie par voie anterieure, sans faire une sternotomie est realisable. Elle doit etre precedee d’un reperage radiologique de la limite superieure du sternum.We report two cases of exceptional first thoracic disc herniation in a 60-year-old man and a 55-year-old woman. The man was treated surgically and the woman medically. Osteoarthritis appeared to be the predominant cause of the disc herniation in both patients. Unlike the usual calcification in the medioposterior position for middle or lower thoracic spine herniations, a soft posterolateral herniation was observed here. The symptoms are limited, as observed in both patients, to a T1 radiculopathy, to be distinguished from C8 radicopathy. Myelopathy is rare. Claude-Bernard-Horner syndrome is not constant but highly suggestive. Both of these signs were absent in our patients. T1-T2 disc herniation should be suspected in patients presenting cervico-brachial medial neuralgia. MRI provides the diagnosis. Anterior surgery can be achieved without sternotomy. Careful radiographic analysis is needed preoperatively to identify the upper limit of the sternum.